squamosamide and Parkinson-Disease

Many major neurodegenerative diseases are associated with proteins misfolding and aggregation, which are also called "neurodegenerative conformational disease". The interaction of gene mutation and environmental factors are probably primary events resulting in oligomer and aggregate formations of proteins. Moreover, the dysfunctions of protein control systems, i.e. the ubiquitin-proteasome system and autophagy-lysosomal system, also contribute to the neurodegenerative process. The present review mainly summarizes protein misfolding and aggregation in the development of neurodegenerative conformational disease and the underling mechanisms, as well as upregulation of heatshock proteins as a promising treatment method for this kind of disease.

Topics: Alzheimer Disease; Animals; Annona; Autophagy; Benzeneacetamides; Heat-Shock Proteins; Humans; Mutation; Neurodegenerative Diseases; Parkinson Disease; Phenols; Plants, Medicinal; Proteasome Endopeptidase Complex; Protein Folding; Ubiquitin

Glial cell line-derived neurotrophic factor (GDNF) has neurotrophic activity for the survival of dopaminergic neurons, which is under active investigation for Parkinson's disease (PD) therapy. FLZ is a potential new drug for PD treatment. However, it is unclear whether neurotrophic activity contributes to the neuroprotective effects of FLZ. Here we found that FLZ markedly improved the function of dopaminergic neurons in primary mesencephalic neuron/glia cultures. Further investigation demonstrated that astroglia were required for FLZ to function as a neurotrophic regulator, as FLZ failed to show neurotrophic effects in the absence of astroglia. We clarified that GDNF was responsible for the neurotrophic effects of FLZ since FLZ selectively stimulated GDNF production, which was confirmed by the finding that the neurotrophic effect of FLZ was attenuated by GDNF-neutralizing antibody. Mechanistic study demonstrated that GDNF induction by FLZ was CREB-dependent and that PI3K/Akt was the main pathway regulating CREB activity, which was confirmed by in vivo studies. We also validated that the induction of GDNF by FLZ contributed to PD treatment in vivo. In conclusion, the present data provided evidence that FLZ had robust neurotrophic effects on dopaminergic neurons through sustained induction of GDNF in astroglia by activating the PI3K/Akt/CREB pathway.

Topics: Acrylamides; Animals; Astrocytes; Benzeneacetamides; Caffeic Acids; Disease Models, Animal; Dopamine; Dopaminergic Neurons; Glial Cell Line-Derived Neurotrophic Factor; Mesencephalon; Neuroglia; Neuroprotective Agents; Parkinson Disease; Phenols; Phosphatidylinositol 3-Kinases; Primary Cell Culture; Rats; Rats, Sprague-Dawley

Parkinson's disease (PD) is a neurodegenerative disease affecting up to 80% of dopaminergic neurons in the nigrostriatal pathway. FLZ, a novel synthetic squamosamide derivative from a Chinese herb, has been shown to have neuroprotective effects in experimental PD models. In this study, we carried out a set of in vitro and in vivo experiments to address the neuroprotective effect of FLZ and related mechanism. The results showed that FLZ significantly improved motor dysfunction and dopaminergic neuronal loss of rats injured by 6-hydroxydopamine (6-OHDA). The beneficial effects of FLZ attributed to the elevation of dopaminergic neuron number, dopamine level and tyrosine hydroxylase (TH) activity. Mechanistic study showed that FLZ protected TH activity and dopaminergic neurons through decreasing α-synuclein (α-Syn) expression and the interaction between α-Syn and TH. Further studies indicated the involvement of phosphoinositide 3-kinases (PI3K)/Akt signaling pathway in the protective effect of FLZ since it showed that blocking PI3K/Akt signaling pathway prevented the expression of α-Syn and attenuated the neuroprotection of FLZ. In addition, FLZ treatment reduced the expression of RTP801, an important protein involved in the pathogenesis of PD. Taken together, these results revealed that FLZ suppressed α-Syn expression and elevated TH activity in dopaminergic neuron through activating Akt survival pathway in 6-OHDA-induced PD models. The data also provided evidence that FLZ had potent neuroprotecive effects and might become a new promising agent for PD treatment.

Topics: alpha-Synuclein; Animals; Apomorphine; Benzeneacetamides; Cell Death; Disease Models, Animal; Dopamine Agonists; Dopaminergic Neurons; Male; Motor Activity; Neuroprotective Agents; Oxidopamine; Parkinson Disease; Phenols; Proto-Oncogene Proteins c-akt; Rats; Rats, Wistar; Repressor Proteins; Signal Transduction; Transcription Factors; Tyrosine 3-Monooxygenase

FLZ, a novel anti-Parkinson's disease (PD) candidate drug, has shown poor blood-brain barrier (BBB) penetration based on the pharmacokinetic study using rat brain. P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP) are two important transporters obstructing substrates entry into the CNS as well as in relation to PD neuropathology. However, it is unclear whether P-gp and BCRP are involved in low BBB permeability of FLZ and what the differences of FLZ brain penetration are between normal and Parkinson's conditions. For this purpose, in vitro BBB models mimicking physiological and PD pathological-related BBB properties were constructed by C6 astroglial cells co-cultured with primary normal or PD rat cerebral microvessel endothelial cells (rCMECs) and in vitro permeability experiments of FLZ were carried out. High transepithelial electrical resistance (TEER) and low permeability for sodium fluorescein (NaF) confirmed the BBB functionality of the two models. Significantly greater expressions of P-gp and BCRP were detected in PD rCMECs associated with the lower in vitro BBB permeability of FLZ in pathological BBB model compared with physiological model. In transport studies only P-gp blocker effectively inhibited the efflux of FLZ, which was consistent with the in vivo permeability data. This result was also confirmed by ATPase assays, suggesting FLZ is a substrate for P-gp but not BCRP. The present study first established in vitro BBB models reproducing PD-related changes of BBB functions in vivo and demonstrated that poor brain penetration of FLZ and low BBB permeability were due to the P-gp transport.

Topics: Adenosine Triphosphatases; Animals; Antiparkinson Agents; ATP Binding Cassette Transporter, Subfamily B, Member 1; ATP Binding Cassette Transporter, Subfamily G, Member 2; ATP-Binding Cassette Transporters; Benzeneacetamides; Biological Transport; Blood-Brain Barrier; Dibenzocycloheptenes; Disease Models, Animal; Endothelial Cells; Indoles; Male; Microvessels; Parkinson Disease; Permeability; Phenols; Quinolines; Rats; Rats, Wistar

The participation of neuroinflammation in the pathogenesis of Parkinson's disease (PD) has long been validated. Excessive activated microglia release a large number of pro-inflammatory factors, damage surrounding neurons and eventually induce neurodegeneration. Inhibition of microglial over-activation might be a promising strategy for PD treatment. FLZ (formulated as: N-(2-(4-hydroxy-phenyl)-ethyl)-2-(2, 5-dimethoxy-phenyl)-3-(3-methoxy-4-hydroxy-phenyl)-acrylamide, the code name: FLZ), a natural squamosamide derivative from a Chinese herb, has been shown to inhibit over-activated microglia and protect dopaminergic neurons in previous studies, but the mechanism remains unclear. In the present study, we further investigated the mechanism in lipopolysaccharide (LPS)-induced in vivo and in vitro PD models. FLZ treatment significantly improved the motor dysfunction of PD model rats induced by intra-nigral injection of LPS and this beneficial effect of FLZ attributed to the inhibition of microglial over-activation and the protection on dopaminergic neurons in the substantia nigra (SN). In vitro mechanistic study revealed that the inhibitive effect of FLZ on microglia was mediated by suppressing Src kinase related inflammatory signaling pathway activation and subsequent NF-κBp65 nuclear translocation, inhibiting nitric oxide (NO) and reactive oxygen species (ROS) production, decreasing nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activation. In conclusion, the present study supports that FLZ exerts neuroprotection against LPS-induced dopaminergic neurodegeneration through its anti-inflammatory effect, which is mediated by suppressing Src tyrosine kinase and the downstream inflammatory signaling pathway. Furthermore, this study defines a critical role of Src tyrosine kinase in neuroinflammation, and suggests that particular tyrosine kinase inhibition may be a potential anti-inflammatory approach for PD treatment.

Topics: Animals; Apomorphine; Benzeneacetamides; Cell Line; Disease Models, Animal; Dopamine Agonists; Dose-Response Relationship, Drug; Encephalitis; Enzyme Activation; Enzyme Activators; Exploratory Behavior; Lipopolysaccharides; Male; Mice; Motor Activity; Parkinson Disease; Phenols; Rats; Rats, Wistar; src-Family Kinases

An HPLC method was established and validated for the determination of compound FLZ, a synthetic novel anti-Parkinson's disease candidate drug, in rat plasma. FLZ and the internal standard bicyclol were extracted from plasma by solid-phase extraction method and analyzed on a Restek C18 column (4.6 x 250 mm, 5 microm) with a mobile phase consisting of methanol and water (60:40, v/v) at a flow rate of 1.0 mL/min. The detection wavelength was set at 320 nm. The calibration curve was linear within the concentration range from 25 to 500 ng/mL (r2 > 0.999), the limit of quantitation was 25 ng/mL and the average recovery was 92.0% with the RSD less than 5.9%. The relative standard deviation for intra- and inter-day precision was less than 3.8 and 6.9%, respectively. The established HPLC method was validated to be a simple, rapid and reliable procedure and applied to study the preclinical pharmacokinetics of FLZ in rat plasma, and it was the first time that the pharmacokinetics of FLZ had been investigated.

Topics: Animals; Benzeneacetamides; Calibration; Chromatography, High Pressure Liquid; Male; Parkinson Disease; Phenols; Rats; Rats, Wistar; Reproducibility of Results; Sensitivity and Specificity

Compound FLZ is a synthetic novel derivative of squamosamide. Previous pharmacological study found that FLZ improved the abnormal behavior and the decrease of dopamine content in striatum in 6-hydroxydopamine (6-OHDA) model mice. 6-OHDA can cause Parkinsonism in experimental animals. The purpose of this paper was to study the protective action of FLZ against 6-OHDA-induced apoptosis and alternations of related signal transduction. The results indicated that FLZ at concentrations of 0.1 microM and 1 microM prevented 6-OHDA-induced apoptosis of SH-SY5Y cells, and inhibited the increase of cytochrome c and Apoptosis-inducing factor (AIF) release and activation of Caspase 3 and NF-kappaB. The results suggested that FLZ has potential neuroprotective effect on 6-OHDA-induced apoptosis of SH-SY5Y cells through regulating related signal-transduction.

Topics: Apoptosis; Apoptosis Inducing Factor; Benzeneacetamides; Caspase 3; Cell Line; Cell Survival; Cytochromes c; Drug Delivery Systems; Models, Biological; Neuroprotective Agents; NF-kappa B; Oxidopamine; Parkinson Disease; Phenols; Signal Transduction